This invention relates to a concrete finishing machine.
The typical method of placing and finishing concrete involves using separate apparatuses for placing concrete over a paving area and for finishing the concrete surface of the paving area at a desired grade. The paving area could be a road, parking lot, airport runway, bridgeway or the like.
Generally, the concrete is discharged onto the paving area from a spreader, pumping boom arrangement or the like at a considerable distance ahead of the concrete finishing machine. Several men with shovels then manipulate the concrete to evenly distribute the concrete for the concrete finishing machine.
The concrete finishing machine follows and extends transversely of the paving area to be paved with concrete. The machine generally consists of a truss spanning the paving area and a finishing carriage movably attached to the truss for movement along the length of the truss. The finishing carriage carries a rotating auger for positioning the concrete to approximate grade and moving excess concrete forward in the direction of machine travel, a rotating cylinder for consolidating and finishing the concrete to grade, and a float pan or drag plate for sealing the concrete surface. The finishing carriage moves in one direction until it reaches the side of the paving area and then reverses direction and travels to the opposite side of the paving area.
Various approaches have been suggested with respect to apparatus for placing and finishing concrete as set forth in the disclosure of the following patents:
______________________________________ Reg. No. Inventor Title ______________________________________ 1,629,276 Kipp Concrete Pavement Finishing Machine 1,878,278 Jaeger Road Or Pavement Making Apparatus 1,993,656 Gardiner Method And Apparatus For Building Roads 3,107,592 Mengel Machine For Spreading Concrete and Other Road Materials 3,156,170 Behrens Placing Plastic Paving Material 3,187,879 Mengel Spreader 3,225,668 Marginniss Method And Apparatus For Distributing Concrete 3,252,390 Martinson Concrete Paving Machine 3,450,011 Godbersen Concrete Finishing Machine 3,541,931 Godbersen Cement Finishing Mechanism Having Adjustable Rotating Drum 3,767,312 Raymond Apparatus For Making Concrete Slabs 4,466,757 Allen Vibrating Screed Including A Spreading Device For Leveling And Distributing Plastic Concrete In Front of the Screed ______________________________________
The practice of placing and/or finishing concrete as described above and disclosed in the above-listed patents presents many shortcomings. The concrete placing operation is generally labor intensive, sometimes requiring seven or eight men to evenly distribute the concrete.
It is also difficult to gauge by visual estimation the proper amount of concrete being placed for the final grade when placement occurs at a distance ahead of the concrete finishing operation. Oftentimes, too much or too little concrete is initially placed. If too much is placed, then the finishing machine and laborers must move large quantities of concrete around the paving area. If too little is placed, then the laborers must place additional concrete at the finishing machine.
Moreover, as the distance and time between the placing and finishing operations increase, problems may develop relative to closing and sealing the concrete because the concrete may have cured significantly before it undergoes the finishing operation. This problem is especially prevalent under circumstances in which the concrete finishing machine is taken out of service unexpectantly for a period of time during the finishing operation.
Previous rotating cylinders on the moving carriage have generally not been completely satisfactory. The rotating cylinders move the excess concrete to either side of the paving area or can spill concrete onto the paving area that has already been finished by the rotating cylinders. Either situation is unsatisfactory because the excess concrete should be plowed forward in the direction of machine travel to fill voids that may exist.
Also, many of the prior art constructions are not suited for maintaining the proper grade when the truss axis is skewed relative to an axis that is substantially perpendicular to the direction of finishing machine travel and are not suited to handle high volumes and rates of concrete placement and finishing. The present invention overcomes such prior art shortcomings.